Switch guard rings for Canon-fit lenses

The “LarkSaver” backstory

As an avid but impatient birder I cover a lot of miles with my Canon DSLR and mirrorless cameras, and various telephoto lenses. One problem I've had too many times is the switches on the lens body get easily knocked and (for example) you suddenly find yourself in manual focus mode, or the stabilizer's turned off, or the focus limiter is tripped. After completely missing the shot on a small group of Horned Larks (which I've never seen since!), I finally decided to make a solution. Since fitting these to my lenses, I haven't had a single incident of shifted switches.

Lenses supported

You can probably adapt for others with the included SCAD files:

• Sigma 100-400mm f/5-6.3 DG OS HSM Contemporary Lens for Canon EF
• Sigma 150-600mm f/5-6.3 DG OS HSM Contemporary Lens for Canon EF
• Canon RF 800mm f/11 IS STM Lens

There are a few fitting options; the Sigma lenses don't have the switches on the same lens segment as the lens foot mount, so can wrap all the way around with a bolt closure (#4). The RF800 has the switches in-line with the foot, so that can clamp the ring in place. Note that you will probably need a longer mounting screw for the foot, and the foot may not be as firmly attached - use these at your (and your camera's) own risk!

Note

I've never actually printed these myself (though they did start the journey that resulted in my MK3s+ purchase) - I had them printed commercially, in ABS with 20% infill (IIRC). I strongly suspect you'll need some clever supports. 

This design is also available on Github under the same username.